Exploring T and S parameters in Vector Meson Dominance models of strong electroweak symmetry breaking
Abstract
We revisit the electroweak precision tests for Higgsless models of strong EWSB. We use the Vector Meson Dominance approach and express S and T via couplings characterizing vector and axial spin-1 resonances of the strong sector. These couplings are constrained by the elastic unitarity and by requiring a good UV behavior of various form- factors. We pay particular attention to the one-loop contribution of resonances to T (beyond the chiral log), and to how it can improve the fit. We also make contact with the recent studies of Conformal Technicolor. We explain why the second Weinberg sum rule never converges in these models, and formulate a condition necessary for preserving the custodial symmetry in the IR.
- Publication:
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Journal of High Energy Physics
- Pub Date:
- March 2012
- DOI:
- 10.1007/JHEP03(2012)046
- arXiv:
- arXiv:1111.3534
- Bibcode:
- 2012JHEP...03..046O
- Keywords:
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- Technicolor and Composite Models;
- Beyond Standard Model;
- High Energy Physics - Phenomenology
- E-Print:
- 35 pages, 7 figures